The overall objective of this program is to enhance our understanding of the mechanisms that regulate wound healing and epithelial mucosal defense against infection with particular reference to the lung epithelium. Because each of the four projects in this program require a coordinated cell culture facility to evaluate in vitro epithelial repair, a cell isolation and culture core is proposed to provide a central resource available to all investigators for evaluating and testing mechanisms relevant to their individual projects. The primary aims of this cell culture core are (1) to provide a mechanism for generating primary cell isolation of alveolar epithelial cells from rat and mouse lungs that can be used to study in vitro mechanisms of epithelial injury and repair, (2) to provide primary isolation of human alveolar epithelial type II cells from cadaver human lungs to evaluate the mechanisms of epithelial injury and repair in human lung epithelium, (3) to provide a centralized location for the measurement of in vitro epithelial wound repair that can be useful for all projects using either primary cell isolation or cell lines. Dr. Matthay and his laboratory have considerable experience with the primary isolation of rodent lung epithelial cell lines, and recently have developed methodology to isolate purified alveolar epithelial type II cells from human cadaver lungs, providing a unique resource for this program. Also, this cell isolation and culture core will provide useful expertise for studying in vitro mechanisms of lung epithelial cell repair.